C/C++使用HTTP协议上传

上传文件：

http://zengrong.net/post/2088.htm

#include <stdio.h>
#include <string.h>

#include <curl/curl.h>

int main(int argc, char *argv[])
{
  CURL *curl;
  CURLcode res;

  struct curl_httppost *formpost=NULL;
  struct curl_httppost *lastptr=NULL;
  struct curl_slist *headerlist=NULL;
  static const char buf[] = "Expect:";

  curl_global_init(CURL_GLOBAL_ALL);

  /* Fill in the file upload field */
  curl_formadd(&formpost,
               &lastptr,
               CURLFORM_COPYNAME, "message",
               CURLFORM_COPYCONTENTS, "hello",
               CURLFORM_END);

  /* Fill in the filename field */
  curl_formadd(&formpost,
               &lastptr,
               CURLFORM_COPYNAME, "filename",
               CURLFORM_FILE,"test.xlsx",
               CURLFORM_CONTENTTYPE, "application/vnd.ms-excel",
               CURLFORM_END);

  curl = curl_easy_init();
  /* initalize custom header list (stating that Expect: 100-continue is not
     wanted */
  headerlist = curl_slist_append(headerlist, buf);
  if(curl) {
    /* what URL that receives this POST */
    curl_easy_setopt(curl, CURLOPT_URL, "http://192.168.1.107/protocol/upload_questions/");
    if ( (argc == ) && (!strcmp(argv[], "noexpectheader")) )
      /* only disable 100-continue header if explicitly requested */
      curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headerlist);
    curl_easy_setopt(curl, CURLOPT_HTTPPOST, formpost);

    /* Perform the request, res will get the return code */
    res = curl_easy_perform(curl);
    /* Check for errors */
    if(res != CURLE_OK)
      fprintf(stderr, "curl_easy_perform() failed: %s\n",
              curl_easy_strerror(res));

    /* always cleanup */
    curl_easy_cleanup(curl);

    /* then cleanup the formpost chain */
    curl_formfree(formpost);
    /* free slist */
    curl_slist_free_all (headerlist);
  }
  return ;
}